Clamping means



Oct. 22, 1940.

J. J. MADDEN cmmrme MEANS Filed Sept. 12, 1938 2 Sheets-Sheet 1 Oct. 22, 1940. J MADDEN I 2,219,014

CLAMPING MEANS Filed Sept. 12, 1938 2 Sheets-Sheet 2 INVENTOR Patented Oct. 22, 1940 UNITED STATES 2,219,014 CLAMPING' MEANS James J. Madden, Aurora, 111., assignor to-All- Steel-Equip (30., Aurora, I ll., a corporation of Illinois Application September 12, 1938, Serial No. 229,503

3 Claims.

The present invention relates to improvements in clamping means.

In the art relating to protective devices for electric wiring it is common to provide boxes 6 known as switch boxes, receptacle boxes, outlet boxes, junction boxes, or the like, which boxes receive the ends of electric wires. Such electric wires are commonly enclosed within metal sheathing which is grounded to the electrical-system. Non-metallic materials are also used for this sheathing. The present invention is particularly applicable to means for clamping this sheathing to the wall of a box into which it enters.

An object of the present invention is to provide improved clamping means for rigidly securing the sheathing of electric wires to a switch box or the like. v

A further object is to provide improved clamping means which may bereadily manipulated to assemble or disassemble the clamping means from the sheathing and the switch box.

A further object is to provide a readily operable clamping means which may be locatedwithin a switch box or the like, whereby to be less easily tampered with.

A further object is to provide an efiicient clamping means which may be manufactured economically. v

A further object is to provide a readily operable clamping means which is well adapted to meet the needs of commercial service.

Further objects will appear as the description proceeds. g

Referring to the drawings- Figure 1 is a sectional view illustrating one embodiment of the present invention; 7

Figure 2 is an elevational view taken in the direction of the arrow 2 in Figure l, the sheathing for the electric wires being omitted, however;

Figure 3 is a view in elevation of a wedging member forming part of the construction illustrated in the preceding figures;

Figure 4 is a sectional View of a modified construction quite similar to the structure shown in Figure 1 but showing the means for operating the clamping means disposed inwardly of a switch box or the like;

Figure 5 is a sectional view of another modification;

Figure 6 is an elevational view taken in the direction of the arrow 6 in Figure 5, the sheathing for the electric wiring being omitted;

Figure 7 is a sectional view illustrating a further modification;

Figure 8 is a view in elevation taken in the direction of the arrow 8 of Figure 7, the sheathing for the electric wiring being omitted;

Figure 9 is a sectional view showing a still further modification; and

Figure 10 is an elevational view taken in the direction of the arrow III of Figure 9.

Referring first to the structure illustrated in Figures 1, 2 and 3, the numeral I0 indicates a box provided with the wall II, which wall II has an aperture I2 therein for the purpose of admitting electric conductors into the interior of the box Ill. The numeral I3 indicates a sheathing for electrical conductors. This sheathing is commonly made of metal and is generally known in the trade as BX cable.

The numeral I4 indicates as a whole a metallic socket member having the cylindrical wall I5 provided at one of its extremities with the inwardly extending flange I6, which flange I6 is adapted to provide an abutment for the sheathing or cable I3. The flange I6 may beomitted, of course, if desired. Intermediate of its length the cylindricall wall I5 is provided with the external flange I8, which may be provided with the longitudinally extending teeth I9 adapted toengage against a side surface of the wall I I to provide a good electrical contact between the socket member I4 and said wall I I. The socket member I4 is split preferably along a diameter at the region thereof opposite to the flange IS. The slots at the diametrically opposed split portions are indicated by the numeral 20. It will be noted that the slots 20 extend throughout most of the length of the socket member I4, whereby a considerable give will be provided in the split end of said member I4.

Intermediate of its length the exterior surface of the cylindrical wall I5 of the socket I4 is beveled out'at opposed regions disposed substantially degrees from the slots 20-40. The numerals 2 I-'2I indicate these beveled out surfaces.

Cooperatively associated with the socket member I4 is the plate 22. This plate is non-rotatably associated with the socket member I4, and in the embodiment of the invention illustrated in Figures 1, 2 and 3 said plate is centrally apertured, as indicated by the numeral 24, for receiving the cylindrical wall I5. To provide this nonrotatable relationship between the socket member I4 and the plate 22, side portions of the cylindrical wall I5 of the member I4 may be flattened, as indicated by the numerals 24a 24a,. The two side walls 25-25 01? the plate 22 embrace said flattened sides 24a-24a loosely, but in a way to prevent rotation of the plate 22 relative to the socket member l4. Extending inwardly from said side walls 25--25 are the opposed inwardly extending lugs 2526 adapted to be located in slots 2|2| in opposite side portions of the cylindrical wall |5 of the socket member |4. Said lugs 2626 are so proportioned relative to the slots 2i|-2|J that the plate 22 may be entered upon the cylindrical wall I5 with the lugs 26-26 moving along the slots 2020. When said lugs 26-45 have reached the region of the slots 21-21 the plate 22 may be moved transversely relative to the axis of the cylindrical wall I5, whereby said lugs 2525 will be disposed within said slots. 2l-2'l and limit movement of the plate 22 longi tudinally of the socket member l4.

The lower wall 23 of the plate 22 is provided with an upper beveled surface 29 adapted to conform to the beveled surface 2| of the cylindrical wall I5 of the socket member M. The upper extremity of the plate 22 is provided with the angularly disposed flange 363. said flange 30 is disposed preferably at an angle of approximately degrees relative to the remainder of the plate 22. Said flange 3.6 is screw-threadedfor the reception of the bolt 3|, the extremity of which is tapered in the shape of a truncated cone, as indicated by the numeral 32. Said tapered extremity 32 of the bolt 3| is adapted to wedge between the beveled out portion 2| and the adjacent wall ll of the box I0.

It will be obvious without detailed explanation that the sheathing l3 may be readily secured to the box IE as follows: The socket member |4 may be slipped through the aperture l2, the plate 22 may be located in position, and the bolt 3| may be lightly turned up, possibly merely by the operators fingers, thereby securing .the socket member l4 tothe box it without exerting suiflcient pressure to collapse the cylindrical wall |5 of the socket member M. The operator will then insert the sheathing or cable l3, locating it against the flange It, and may then apply the force necessary, by means of a screw driver or the like, to turn up the bolt 3| to cause the socket member l4 to grip the sheathing or cable l3 and to produce the wedging action of the plate 22 which clamps the box wall between the annular flange H3 and .the plate 22.

The structure illustrated in Figure 4 will be understood without detailed explanation. The structure in Figure 4 differs from that above described in connection with Figures 1, 2 and 3 in that the plate 22 and ,the operating screw 3| are disposed inwardly of the box. This construction has the advantage that the screw 3| may not be tampered with unless access is had to the box H). In many cases such access is impossible, or at least difficult, to unauthorized persons. Ac cording to the structure shown in Figure 4, the flange 56a corresponding to the flange l6 of Figure 1 is located at the split end of the socket member |4. Said split end containing the flange 6a is disposed inwardly of the box l0. Assembly and disassembly may be readily accomplished in the manner described above in connection with Figures 1, 2 and 3.

The construction shown in Figures 5 and 6 is similar in many respects to that shown in Figures 1 to 3. In the embodiment illustrated in Figures 5 and 6 a plate 33 is provided which has the flange 34 extending at right angles therefrom. Said flange 34 is screw-threaded for-the reception of a bolt 35, which may have the pointed extremity 3B for engagement with the adjacent split portion of the. .cylindricalwall.|5,of,,the

"side, as indicated by the numeral 39.

split portions of the cylindrical wall |5, resulting in the tight gripping of the sheathing I3.

Figures 7 and 8 illustrate a modified construction. In this embodiment of the present invention a socket member 37 is provided having the cylindrical wall 38, which is split along only one The side of the socket member 31 opposite to the split 39 is flat, as indicated by the numeral 49, said fiat surface 40 being preferably substantially at right angles to that diameter of the socket member 3! which bisects the split 39. The plate member 4| is quite similar to the plate member 33 illustrated in Figures 5 and 6, but omits, with their functions, the lugs 26 shown in said figures. Said plate member fits the flattened side surface 40 of the socket member 3'! sufliciently closely to prevent relative rotation between said plate member and said socket member. Said plate member 4| is provided with the flange 43 disposed at right angles to the body of the plate member 4|, which flange 43 is screw-threaded for the reception of the bolt 44, which bolt has the pointed extremity 45 adapted to engage in a corresponding recess 46 in the cylindrical wall of the socket member 31. The axis of the bolt 44 should be off center with respect-to the cyiindnical wall 31 and should be located in the chord intersecting said cylindrical wall in a region adjacent to the split 39. Said plate 4| is provided with the beveled edge 41 adapted to conform to the beveled portion 2| of the socket member 31.

Turning down of the bolt M will have the result of exerting an upward pull upon the plate member 4| as the parts are viewed in Figures 7 and 8, drawing the flange 48 into tight engagement with the wall I I of the box 6. At the same time the turning down of the bolt 44 will exert a contracting force upon the split cylindrical wall of the socket member 3.1, urging the cylindrical wall into tight gripping engagement with the sheathing l3. The socket member ill is readily contractible because, at the region opposite to the split 39, it is reduced in cross-section by reason of the flattened surface 40.

In the embodiment of the present invention illustrated in Figures 9 and 10 the socket member 49 is split along one side as indicated by the numerals 53-50. Said socket member has a flattened side 5| opposite to the split 59, whereby to be more readily contractible. Said socket member 49 is provided with the annular flange 53 adapted to engage against the wall ll of the box I0. Spaced from the flange 53 are the beveled portions ti l-54 located symmetrically with relation to the diameter which bisects the split 59, which taper toward the flange 53. A plate 55 is provided which is annular in form and has a beveled inner edge 55 adapted to conform with the beveled portions 54 of the socket member 49. The plate 55 extends through a circumference of somewhat less than 360 degrees, and the extremities of said annular plate are provided with the outstanding lugs 51 and 58. The lug 5"! is screw-threaded for the reception of the bolt 53,

against the outer surface of the lug 58.

It will be understood that when it is desired to clamp the sheathing l3 to the box in the construction shown in Figures 9 and 10, said sheathing l 3 will be inserted into the socket member 49. The annular plate 55 will have been mounted upon the socket member 49. The bolt 59 will be tightened, resulting in a wedging action between the beveled surface 56 of the annular. plate 55 and the beveled surfaces 5454 of the socket member 49, drawing the flange 53 into tight engagement with the wall ll of the box Ill. The same tightening movement of the bolt 59 will exert a compressive action upon the split socket.

member 49, tightly gripping the sheathing l3.

Though certain preferred embodiments of the present invention have been described in detail, many modifications Will occur to those skilled in the art. It is intended to cover all such modifications that fall within the scope of the appended claims.

What is claimed is- 1. Clamping means comprising, in combination, a cylindrical member having an annular shoulder adapted to engage the wall of a box, a plate mem-- ber disposed in encircling relationship with said cylindrical member and adapted to wedge said cylindrical member axially relative to said wall,

and threaded means carried by said plate member adapted to exert a force against said cylindrical member to produce such wedging action.

2. Clamping means comprising, in combination, a cylindrical member split through at least a portion of its length, said cylindrical member having a flange adapted to engage the wall of a box, said cylindrical member having at least a portion of its circumference beveled, plate means adapted to engage the opposite side of said wall, said plate means being provided with a beveled portion adapted to cooperate with said beveled portion of said cylindrical member for drawing said flange into tight engagement with said wall.

3. Clamping means comprising, in combination, a contractible cylindrical member having an annular shoulder provided with teeth adapted to engage the wall of a box, a plate member disposed in encircling relationship with said cylindrical member and adapted to Wedge said cylindrical member axially relative to said wall, and threaded means adapted to react against said plate member and said cylindrical member to produce such wedging action and to contract said cylindrical member.

JAMES J. MADDEN. 

